Communications terminal and method

ABSTRACT

A communications terminal includes a transmitter to transmit signals, a receiver to receive signals, and a controller to control the transmitter and receiver. The controller includes an input buffer receiving data packets for transmission. The controller can identify whether the received data packets are delay tolerant or non-delay tolerant, to determine a current state for communications for transmitting the data packets and based on predetermined conditions including a current state for radio communications, an amount of the delay tolerant data packets in the input buffer, and an amount of the non-delay tolerant packets in the input buffer, either transmit the non-delay tolerant data packets or transmit the non-delay tolerant data packets and the delay tolerant data packets from the input buffer to a mobile communications network using the transmitter, or maintain the delay tolerant or non-delay tolerant data packets in the input buffer until the predetermined conditions are satisfied.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is based on PCT filing PCT/GB2014/052000 filedJul. 2, 2014, and claims priority to European Patent Application 13 179483.6, filed in the European Patent Office on Aug. 6, 2013, the entirecontents of each of which being incorporated herein by reference.

TECHNICAL FIELD OF THE DISCLOSURE

The present disclosure relates to communications terminals and methodsfor communicating and wireless communications networks and methods ofcommunicating via wireless communications networks.

BACKGROUND OF THE DISCLOSURE

Third and fourth generation mobile telecommunication systems, such asthose based on the 3GPP defined UMTS and Long Term Evolution (LTE)architecture are able to support more sophisticated services than simplevoice and messaging services offered by previous generations of mobiletelecommunication systems.

For example, with the improved radio interface and enhanced data ratesprovided by LTE systems, a user is able to enjoy high data rateapplications such as mobile video streaming and mobile videoconferencing that would previously only have been available via a fixedline data connection. The demand to deploy third and fourth generationnetworks is therefore strong and the coverage area of these networks,i.e. geographic locations where access to the networks is possible, isexpected to increase rapidly.

The anticipated widespread deployment of third and fourth generationnetworks has led to the parallel development of a class of devices andapplications which, rather than taking advantage of the high data ratesavailable, instead take advantage of the robust radio interface andincreasing ubiquity of the coverage area. Examples include so-calledmachine type communication (MTC) applications, which are typified bysemi-autonomous or autonomous wireless communication devices (i.e. MTCdevices) communicating small amounts of data on a relatively infrequentbasis. Examples include so-called smart meters which, for example, arelocated in a customer's house and periodically transmit information backto a central MTC server data relating to the customers consumption of autility such as gas, water, electricity and so on. Other examplesinclude medical devices which are continuously or intermittentlytransmitting data such as for example measurements or readings frommonitors via a communications network to a server, and automotiveapplications in which measurement data is gathered from sensors on avehicle and transmitted via a mobile communications network to a serverattached to the network.

Whilst it can be convenient for a terminal such as an MTC type terminalto take advantage of the wide coverage area provided by a third orfourth generation mobile telecommunication network there are at presentdisadvantages. Unlike a conventional third or fourth generation mobileterminal such as a smartphone, an MTC-type terminal is preferablyrelatively simple and inexpensive. The type of functions performed bythe MTC-type terminal (e.g. collecting and reporting back data) do notrequire particularly complex processing to be performed. Furthermorethese more simplified devices may be battery operated and may berequired to be deployed for a significant amount of time before thebatteries are replaced. Therefore power conservation is an importantconsideration. Furthermore it is always important to utilise theresources of a mobile communications network as efficiently as possible.However efficient use of communications resources and conservation ofpower are applicable aims generally to all types of communicationsterminals.

SUMMARY OF THE DISCLOSURE

According to an example embodiment of the present disclosure there isprovided a communications terminal comprising a transmitter configuredto transmit signals to a wireless communications network via a wirelessaccess interface provided by the wireless communications network. Thecommunications terminal also comprises a receiver configured to receivesignals from the wireless communications network, and a controllerconfigured to control the transmitter and the receiver to transmit andreceive the signals, wherein the controller includes an input buffer forreceiving data packets for transmission as the signals via the wirelessaccess interface. The controller is configured to identify whether thereceived data packets are delay tolerant or non-delay tolerant, todetermine in combination with signals received from the receiver anindication of a current state for radio communications formed by thewireless access interface for transmitting the data packets via thewireless access interface, and in accordance with the predeterminedconditions which include a current state for radio communications and anamount of the delay tolerant data packets in the input buffer and anamount of the non-delay tolerant packets in the input buffer either totransmit the non-delay tolerant data packets or to transmit thenon-delay tolerant data packets and the delay tolerant data packets fromthe input buffer to the mobile communications network using thetransmitter, or maintaining the delay tolerant or non-delay tolerantdata packets in the input buffer until the predetermined conditions aresatisfied.

Embodiments of the present technique can provide an arrangement in whichdata packets which can be classified into at least delay tolerant andnon-delay tolerant data packets are transmitted by a communicationsterminal in a way which can conserve the power of the communicationsterminal and more efficiently utilise the communications resources of awireless access interface provided by a mobile communications network.As will be appreciated delay tolerant data packets can be delayed for apredetermined time or indefinitely and so therefore buffered in an inputbuffer before being transmitted. Depending on currently experiencedradio conditions for transmitting the data packets a communicationsterminal can buffer the input packets data packets for delay tolerantdata packets until the channel is in a state in which communicationsresources can be used efficiently to transmit the data packets.Furthermore, signalling and control data is required to be transmittedfrom both the communications terminal and the mobile communicationsnetwork before a communications terminal can access communicationsresources for transmitting the data packets. Therefore the more datapackets which can be transmitted in any connection session, such as whena communications terminal has established a bearer via the wirelessaccess interface the more efficient the transmission of the datapackets. Thus by queuing the data packets in an input buffer until apredetermined number of the delay tolerant data packets are received, amore efficient use of radio communications resources can be achieved.However communications terminals also need to transmit the non-delaytolerant data packets. If one or more of the non-delay tolerant datapackets are present in the input buffer then depending on the state ofthe radio communications channel, the communications terminal cantransmit the non-delay tolerant data packets with the delay tolerantdata packets in order to achieve both an efficiency gain in the use ofthe radio communications resources and conserving an amount of poweravailable to the mobile communications terminal. The power conservationis achieved in one example by only transmitting the data packets whenthe state for radio communications exceeds a predetermined qualitymetric. Thus the communications terminal only transmits data packets asa function of the state of the radio communications channel and thenumber of delay tolerant and non-delay tolerant data packets present inan input buffer. Accordingly, with this combination of features, acommunications terminal is both able to conserve power and utiliseresources of the communications wireless access interface moreefficiently.

In one example embodiment the transmission of the delay tolerant datapackets and non-delay tolerant data packets is determined in accordancewith an amount of power available to the communications terminal incombination with a current state for radio communications. Thusnon-delay tolerant data packets are prioritised for transmission beforedelay tolerant data packets depending on whether or not the poweravailable to the communications terminal is below or above apredetermined threshold.

As will be appreciated various combinations of states for radiocommunications and numbers of data packets present in an input buffercan be combined in order to achieve an improvement in both powerconservation for the communications terminal and an efficiency withwhich communications resources are used.

In one example embodiment a decision as to whether to grant up the linkresources to a communications terminals to transmit data packets isdetermined by an infrastructure equipment of a mobile communicationsnetwork as a function of the number of delay tolerant data packets andnon-delay tolerant data packets in an input buffer of the communicationsterminal with a current state for radio communications.

Various further aspects and features of the present disclosure aredefined in the appended claims and include a method for communicatingand infrastructure equipment.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments of the present disclosure will now be described by way ofexample only with reference to the accompanying drawings wherein likeparts are provided with corresponding reference numerals and in which:

FIG. 1 is a schematic block diagram of a mobile communications systemwhich includes communications terminals (UE) and a base station(eNodeB);

FIG. 2 is a schematic representation of ten sub frames of a downlinkpart of a wireless access interface;

FIG. 3 is a schematic representation of resources of subcarriers andsymbols for a sub frame showing in FIG. 2;

FIG. 4 is a schematic representation of the makeup of a frame and subframes and timeslots of an uplink of a wireless access interfaceprovided by the communications system showing in FIG. 1;

FIG. 5 is a more detailed representation of the makeup of a sub frame ofthe frame shown in FIG. 4 for the uplink of the wireless accessinterface which includes an uplink control channel (PUCCH) and an uplinkshared channel (PUCCH);

FIG. 6 represents a typical message exchange which is required in orderto access resources of an uplink shared channel for transmitting datafrom the UE to an eNodeB;

FIG. 7 is a schematic block diagram of an example communicationsterminal which may be used to implement an example embodiment of thepresent technique;

FIG. 8 is a schematic block diagram of an example of the controllershown in FIG. 7 which is adapted to transmit data packets in dependenceupon a number and a type of data packets to be transmitted and a currentstate of radio communications;

FIG. 9 is a flow diagram providing one example operation of acommunications terminal operating in accordance with the presenttechnique;

FIG. 10 is a schematic representation in graphical form showingpredetermined conditions of radio channel with respect to threethresholds A, B and C of quality metric;

FIG. 11 is a flow diagram illustrating the operation of a controller todetermine whether or not to transmit the data packets in accordance withtheir type and an amount of the data packets of each type and includinga current state of a power supply available to a communicationsterminal;

FIG. 12 is an example mobile communications system embodying the presenttechnique;

FIG. 13 is a schematic representation of a message exchange in which acommunications terminal transmits a buffer status and signallingrequests to a base station (eNodeB); and

FIG. 14 is a schematic flow diagram including a message exchange whichillustrates an operation in which a communications terminal transmitsmeasurement reports and buffer status to a mobile communications networkto enable a base station of a network to determine whether predeterminedconditions have been met to transmit data packets from an input bufferof the communications terminal.

DESCRIPTION OF EXAMPLE EMBODIMENTS Example Network

FIG. 1 provides a schematic diagram illustrating the basic functionalityof a conventional mobile communications system. In FIG. 1, a mobilecommunications network includes a plurality of base stations 101connected to a core network 102. Each base station provides a coveragearea 103 (i.e. a cell) within which data can be communicated to and fromcommunications terminals 104. Data is transmitted from a base station101 to a communications terminal 104 within a coverage area 103 via aradio downlink. The data is transmitted from a communications terminal104 to a base station 101 via a radio uplink. The core network 102routes the data to and from the base stations 104 and provides functionssuch as authentication, mobility management, charging and so on. Thebase stations 101 provide a wireless access interface comprising theradio uplink and the radio downlink for the communications terminals andform examples of infrastructure equipment or network elements for themobile communications network, and may be, for the example of LTE, anenhanced Node B (eNodeB or eNB).

The term communications terminals will be used to refer to acommunications devices or apparatus which can transmit or receive datavia the mobile communications network. Other terms may also be used forcommunications terminals such as personal computing apparatus, remoteterminal, transceiver device or user equipment (UE) which may or may notbe mobile. The term UE will be used in the following descriptioninterchangeably with communications terminal.

Example Down-Link Configuration

Mobile telecommunications systems such as those arranged in accordancewith the 3GPP defined Long Term Evolution (LTE) architecture use anorthogonal frequency division multiplex (OFDM) based radio accessinterface for the radio downlink (so-called OFDMA) and the radio uplink(so-called SC-FDMA). Data is transmitted on the radio uplink and on theradio downlink on a plurality of orthogonal sub-carriers. FIG. 2 shows aschematic diagram illustrating an OFDM based LTE downlink radio frame201. The LTE downlink radio frame is transmitted from an LTE basestation and lasts 10 ms. The downlink radio frame comprises tensub-frames, each sub-frame lasting 1 ms. A primary synchronisationsignal (PSS) and a secondary synchronisation signal (SSS) aretransmitted in the first and sixth sub-frames (conventionally numberedas sub-frame 0 and 5) of the LTE frame, in the case of frequencydivision duplex (FDD) system. A physical broadcast channel (PBCH) istransmitted in the first sub-frame of the LTE frame. The PSS, SSS andPBCH are discussed in more detail below.

FIG. 3 provides a schematic diagram providing a grid which illustratesthe structure of an example of a conventional downlink LTE sub-frame.The sub-frame comprises a predetermined number of symbols which aretransmitted over a 1 ms period. Each symbol comprises a predeterminednumber of orthogonal sub-carriers distributed across the bandwidth ofthe downlink radio carrier.

The example sub-frame shown in FIG. 3 comprises 14 symbols and 1200sub-carriers spaced across a 20 MHz bandwidth. The smallest unit onwhich data can be transmitted in LTE is twelve sub-carriers transmittedover one sub-frame. For clarity, in FIG. 3, each individual resourceelement is not shown, but instead each individual box in the sub-framegrid corresponds to twelve sub-carriers transmitted on one symbol.

FIG. 3 shows resource allocations for four communications terminals 340,341, 342, 343. For example, the resource allocation 342 for a firstcommunications terminal (UE 1) extends over five blocks of twelvesub-carriers, the resource allocation 343 for a second communicationsterminal (UE2) extends over six blocks of twelve sub-carriers and so on.

Control channel data is transmitted in a control region 300 of thesub-frame comprising the first n symbols of the sub-frame where n canvary between one and three symbols for channel bandwidths of 3 MHz orgreater and where n can vary between two and four symbols for channelbandwidths of 1.4 MHz. The data transmitted in the control region 300includes data transmitted on the physical downlink control channel(PDCCH), the physical control format indicator channel (PCFICH) and thephysical HARQ indicator channel (PHICH).

The PDCCH contains control data indicating which sub-carriers on whichsymbols of the sub-frame have been allocated to specific communicationsterminals (UEs). Thus, the PDCCH data transmitted in the control region300 of the sub-frame shown in FIG. 3 would indicate that UE1 has beenallocated the first block of resources 342, that UE2 has been allocatedthe second block of resources 343, and so on. In sub-frames where it istransmitted, the PCFICH contains control data indicating the duration ofthe control region in that sub-frame (i.e. between one and four symbols)and the PHICH contains HARQ (Hybrid Automatic Request) data indicatingwhether or not previously transmitted uplink data has been successfullyreceived by the network.

In certain sub-frames, symbols in a central band 310 of the sub-frameare used for the transmission of information including the primarysynchronisation signal (PSS), the secondary synchronisation signal (SSS)and the physical broadcast channel (PBCH) mentioned above. This centralband 310 is typically 72 sub-carriers wide (corresponding to atransmission bandwidth of 1.08 MHz). The PSS and SSS are synchronisationsequences that once detected allow a communications terminal 104 toachieve frame synchronisation and determine the cell identity of thebase station (eNodeB) transmitting the downlink signal. The PBCH carriesinformation about the cell, comprising a master information block (MIB)that includes parameters that the communications terminals require toaccess the cell. The data transmitted to individual communicationsterminals on the physical downlink shared channel (PDSCH) can betransmitted in the remaining blocks of communications resource elementsof the sub-frame.

FIG. 3 also shows a region of PDSCH containing system information andextending over a bandwidth of R₃₄₄. Thus in FIG. 3 the central frequencycarries control channels such as the PSS, SSS and PBCH and thereforeimplies a minimum bandwidth of a receiver of a communications terminal.

The number of sub-carriers in an LTE channel can vary depending on theconfiguration of the transmission network. Typically this variation isfrom 72 sub carriers contained within a 1.4 MHz channel bandwidth to1200 sub-carriers contained within a 20 MHz channel bandwidth as shownin FIG. 3. As is known in the art, subcarriers carrying data transmittedon the PDCCH, PCFICH and PHICH are typically distributed across theentire bandwidth of the sub-frame. Therefore a conventionalcommunications terminal must be able to receive the entire bandwidth ofthe sub-frame in order to receive and decode the control region.

Example Up-Link Configuration PUSCH Structure

According to an example embodiment the up-link of a wireless accessinterface which operates in accordance with LTE is under the control ofthe eNodeB, which receives buffer status reports (BSR) from UEs to aidscheduling decisions. As with the down-link, the up-link includes acommunications channel which provides shared resource known as aphysical up-link shared channel (PUSCH) providing resources, which aregranted in downlink control information (DCI) messages sent on PDCCH.Communications resources are granted to UEs on a resource block group(RBG) basis, where an RBG can contain two, three or five RBs. The grantof PUSCH resources are in contiguous frequency resources to allowtransmission with a low cubic metric since this improves power amplifierefficiency. The exception to this is that, from LTE Rel-10, PUSCH may begranted in two separate ‘clusters’, with each cluster being individuallyin contiguous frequency resources. More details can be found relevant3GPP specifications, for example TS 36.211, TS 36.212, TS 36.213 and TS36.331.

FIG. 4 provides an example representation of an uplink frame structure.As shown in FIG. 4, each frame of the uplink is comprised of 10sub-frames in correspondence with the downlink. Each of these sub-framesis comprised of two time slots 401, 402. Each slot is comprised of sevensymbols in the time domain, and in the frequency domain each of thesymbols provides a plurality of subcarriers which are assigned to thesame UE. The resource blocks are assigned in the frequency domain on thebasis of 12 subcarriers so that a UE may be assigned N×12 subcarriers inthe frequency domain. Typically, in accordance with a conventionaloperation, a UE is assigned all of the seven symbols in the time slot401, 402. As shown in FIG. 4, two examples 404, 406 represent thesymbols in each slot which include the PUSCH 408 which, as explainedabove provides shared physical channel for uplink resources and amodulation reference symbol (DM-RS) 410. Each of the symbols in the timeslot includes a cyclic-prefix CP 412 which in correspondence with theprinciples of OFDM operation provides a repetition of the samples fromthe wanted channel in a guard period in order to allow for inter-symbolinterference.

PUCCH Structure

FIG. 5 provides a representation of the structure of a sub-frame for theuplink in the frequency domain. As indicated above each sub-frame iscomprised of two time slots 401, 402 within which there is transmittedseven symbols in the time domain and in the frequency domain each symbolis comprised of sub-carriers allocated to the same UE on the basis ofN×12 subcarriers. However FIG. 5 is a simplified presentation of theup-link which does not shown the transmission of individual symbols, butshows an example implementation of an uplink control channel which forthe example of LTE would be the physical uplink control channel (PUCCH).

As shown in FIG. 5 resource blocks which are allocated to a UE from theshared physical channel PUSCH occupy a central portion of the frequencyband 420 whereas the PUCCH is formed at the edges of the frequency band422, 424. The PUCCH region is therefore two RBs, one in each slot of asub-frame, which are positioned close to opposite ends of the systembandwidth. Precisely which RBs a PUCCH is allocated depends on theuplink control information (UCI) it is carrying. The format of the PUCCHand on how many RBs the eNodeB allocates in total for PUCCH in asub-frame. Unlike the PUSCH and the PDSCH, for the exampleimplementation of LTE, the resources for PUCCH are not signalledexplicitly on PDCCH, but are instead signalled by RRC configurationcombined, in some cases, with implicit information relating to thelocation of PDCCH. The RRC configuration itself is partly cell-specificand partly UE-specific.

For the example of LTE networks, in Rel-8 and Rel-9, a UE never hasPUSCH and PUCCH in the same sub-frame to preserve the low cubic-metricof the transmission. Therefore, when UCI is to be transmitted in asub-frame where the UE is to have PUSCH, the UCI is multiplexed ontoPUSCH and PUCCH is not sent. From Rel-10, simultaneous PUSCH and PUCCHcan be configured.

As shown in FIG. 5, the PUCCH is comprised of different formats. ThePUCCH formats convey UCI as follows:

Format 1: Scheduling Request (SR)

Format 1a: 1-bit HARQ ACK/NACK with or without SR

Format 1b: 2-bit HARQ ACK/NACK with or without SR

Format 2: CSI in 20 coded bits (with 1- or 2-bit HARQ ACK/NACK inextended CP)

Format 2a: CSI and 1-bit HARQ ACK/NACK

Format 2b: CSI and 2-bit HARQ ACK/NACK

Format 3: Multiple ACK/NACKs for carrier aggregation with optional SR

Transmission of Data Depending on Channel State

As mentioned above the embodiments of the present technique provide anarrangement in which a UE can more efficiently communicate via thewireless access interface in order to both save power which is availableto the UE and make communicating data more efficient with respect to anoverhead of signalling which is required to be communicated moreefficient.

As will be appreciated in accordance with the present example of LTEcommunications, and as explained above both the transmission of data onthe uplink and the downlink is via shared resources. Thus the UEreceives data on the downlink transmitted on the PDSCH which is a shareddownlink channel and transmits data on the uplink on the PUSCH which isa shared uplink channel. In order to gain access to the PUSCH, typicallya UE performs a negotiation with the eNodeB 101 as presented in asimplified form as shown in FIG. 6. As shown in FIG. 6, in order totransmit the data on the uplink shared channel the UE 104 transmits arandom access request message in a PRACH channel 600 in an uplink randomaccess channel to the eNodeB 101. The eNodeB 101 responds bytransmitting a response in the downlink control channel (PDCCH) 602 inwhich the UE is directed to receive a response message from the PDSCH.The response message provides the UE with an allocation of resources onthe uplink shared channel (PUSCH). The UE then transmits data on thePUSCH to the eNodeB and receives acknowledgements for each of the datapackets sent using a downlink ACK/NACK message 606. The UE continues totransmit data via the PUSCH and receives corresponding ACK/NACK messages608, 610 until all the data packets in an input buffer of the UE havebeen transmitted.

As will be appreciated from the message exchange required to transmitdata on the uplink shared channel, a significant amount of signallingmessages 600, 602, 606, 610 have to be transmitted in order for the datato be transmitted on the uplink shared channel (PUSCH) via data carryingtransmissions 604, 608. Therefore an amount of communications resourcesrequired to transmit signalling messages which are required in an activetransmission by the UE until the shared channel resources are released,compared with the amount of data transmitted provides a measure ofefficiency. Therefore the more data is transmitted the more efficientlythe communications resources are being used in order to gain access tothe shared channel (PUSCH) as a ratio of the signalling resourcesrequired.

As will be appreciated a mobile communications terminal (UE) may betypically mobile and therefore power limited. As will be appreciatedtransmitting data at a time when radio coverage is poor and thereforethe conditions for radio communications are poor in respect of a qualityof a radio communications channel may require more power and morecommunications resources than when the conditions for radiocommunications are good. This is because for example, a greater amountof processing may be required in terms of error correction encoding andprocessing requiring a greater amount of data to be communicatedcompared with a situation when the channel state is good and thereforean amount of error correction and encoding can be reduced. Furthermore,for example when the channel state for radio communications is poor thena transmission power of signals representing the data must be increasedin order to effectively communicate the data. In another example agreater number of “NACK” messages may be received, when the channelstate is poor, in the message exchange represented in FIG. 6, requiringa greater number of repeated transmissions. Therefore the poorer thechannel quality the greater the amount of transmission power, which maybe used by a UE to transmit data.

Example Embodiment of the Present Technique

FIG. 7 provides an example block diagram providing a simplifiedrepresentation of components, which may be required to form an examplecommunications terminal (UE). In FIG. 7 a UE 104 is shown to include atransmitter 700 and a receiver 702 which operate to transmit and receivesignals respectively via the wireless access interface, for example bythe LTE uplink and downlink described with reference to FIGS. 1 to 6.The UE 104 is controlled by a controller 704 which controls thetransmitter 700 and receiver 702 to transmit and to receive the datausing radio signals. A processor 706 may operate to provide high layerfunctions such as applications programs and data packet processing suchas internet protocol or UDP or similar protocols in order to transmitdata packets, for example from one IP address to another IP address viathe mobile communications network. Thus the data packets may be receivedon an input 708 and fed to the processor 706 which feeds the datapackets via the controller 704 which controls the transmitter totransmit signals representing the data packets via an antenna 710.

In accordance with an example embodiment of the present technique FIG. 8provides a schematic block diagram of parts which are required todifferentiate transmission of data packets fed from a processor 706 tothe controller 704 from a connecting channel 707.

As shown in FIG. 8 the controller 704 includes an input data buffer 720which receives data packets from a data packet receiver 722 and routesthe data packet into each of a plurality of data packet queues whichrespectively queue data packets of different types. Thus each of thedata packet queues 724, 726, 728 is arranged to receive and store datapackets which have been identified as corresponding to a specifictraffic type as identified by the data packet receiver 722. In oneexample the data packets are internet protocol data packets and areidentified from the traffic type in the header, for example best effort,delay tolerant or non-delay tolerant. The input data buffer 720therefore includes for example an input data queue for delay tolerantdata 724 and an input data queue for non-delay tolerant data 726. Datapackets which are fed out of the input buffer are fed to an aggregator730 which forms the data packets together for transmission via thetransmitter 700.

Traffic Types

As explained above, the data packet receiver 722 is configured toidentify and characterise a respective type of the received packets intoat least delay tolerant and non-delay tolerant data packets. Theidentification of the different packet types can be achieved, forexample, by inspecting the header of the data packets, which accordingsome standards can provide an indication of the respective packet typeand therefore how the data packets should be treated. In other examplesinformation from an application program can provide an indication of thetraffic type. The following provides a non-limiting set of examples:

Traffic Types:

Maximum delay of non-delay tolerant traffic

SPS (semi-persistence scheduling) data (which is typically used forVoice over IP traffic in LTE i.e. real-time)

Guaranteed bit rate or non-guaranteed bit rate

Logical channel priority

QoS attribute in LTE/SAE

-   -   ARP (Allocation and Retention priority)    -   QCI (QoS Class Identifier)    -   Application type        Types of Application:

Meter reading

Fire alarm

Emergency call

According to an example embodiment therefore, the input buffer 720includes as a minimum an input queue 724 for delay tolerant data and aninput queue 726 for non-delay tolerant data. The status of each of theinput queues 724, 726, 728 within the input buffer 720 are fed to atransmission controller 732 which controls the transmission of the datapackets within the input buffer 720 using the aggregator 730 and thetransmitter 700 in accordance with predetermined conditions. Thepredetermined conditions include a current state of a radio channel forcommunicating the data packets from the transmitter to the eNodeB of thecommunications network and an amount of data packets within the inputqueues of the input buffer 720. One example will be explained shortly.

-   -   The state of the channel for communicating data packets via the        uplink of the wireless access interface can in one example be        determined from signals received on the downlink. In one example        the eNodeB 101 reports back to the UE 104 of a state of received        signals from the UE therefore deriving a state of the channel        for transmission on the uplink. In another example the UE is        able to assess the current state of the radio conditions for        transmitting data on the uplink in accordance with a number of        negative acknowledgements (NACK) transmitted to the UE on the        downlink following transmission of a data packet on the uplink.        Accordingly, possible measurement results include: Reference        Signal Received Power (RSRP) or Reference Signal Received        Quality (RSRQ). Possible threshold is RSRP above X [dBm], RSSP        above x [dB].    -   Channel Quality Indication (CQI) (wideband/sub-band)    -   Power Head room of UE

In a further example the transmission controller 732 also receives anindication of a current level of power which is available to the UE fortransmitting or receiving signals using a power monitor 740. The powermonitor 740 is connected via an input channel 742 to a battery or powersource which provides an indication of a relative amount of power whichis available to the UE for transmitting and receiving data. As will beexplained in the examples below in one example the transmissioncontroller 732 determines whether or not to transmit data from the inputbuffer 720 in dependence upon an amount of power which is available tothe UE as provided by the power monitor 740 to the transmissioncontroller 732.

In another example the receiver 702 provides information to a coverageinformation processor 750 which determines a relative metric for radiocoverage currently being received by the UE from signals received fromthe eNodeB of the mobile communications network. The coverageinformation unit 750 is therefore able to provide a further exampleindication of a relative state of radio communications for the UE whichis used by the transmission controller 732 to schedule the transmissionof the data packets from the input buffer 720 via the transmitter 700.

One example embodiment of the present technique is illustrated by theoperation of the transmission controller 732 by the flow diagram shownin FIG. 9. The flow diagram presented in FIG. 9 therefore provides oneexample operation of the transmission controller 732 to transmit thedata packets from the input buffer in accordance with a relative amountof the different types of data packets within the input buffer incombination with the radio conditions currently experienced by the UE.FIG. 9 is therefore summarised as follows:

S1. A communications terminal is configured to transmit and receive datavia a wireless access interface provided by a wireless communicationsnetwork. The communications terminal receives data packets fortransmission by the communications terminal via the wireless accessinterface to the mobile communications network.

S2. The communications terminal stores the received data packets in aninput buffer that identifies a predetermined type to which each of thedata packets belongs.

S4. The communications terminal identifies and allocates the datapackets to different queues or parts of the input data buffer so that atransmission controller can determine how many of each of the differenttypes of data packets there are present in the input buffer.

S6. The communications terminal determines a current state for radiocommunications formed by the wireless access interface for transmittingor receiving the data packets. In particular the communications terminalis concerned with the current radio conditions for transmitting the datapackets. The radio conditions include whether the communicationsterminal is or has recently handed over from one base station to anotherchanging a tracking area for example or the current state of the radiochannel in respect of a quality of data communications via the shareduplink channel.

S8. The communications terminal then compares the current state of theradio communications channel and an amount of data packets in the inputbuffer to determine whether or not to transmit the data packets and ifso whether these should be the non-delay tolerant data packets or thedelay tolerant data packets or both.

S10. Depending on the current state of the radio communications channelthe communications terminal may transmit the non-delay tolerant datapackets. Since these data packets are not tolerant to delays, providedthe radio communications channel is at a minimum quality level, thecommunications terminal transmits the non-delay tolerant data packetswithout further delay.

S12. If the current channel state is better than the channel statedetermined in S10 and such that the delay tolerant and non-delaytolerant data packets can be transmitted then the communicationsterminal determines that the channel state is enough to transmit thenon-delay tolerant data packets from the input buffer and also transmitsthese with the delay tolerant data packets from the input buffer. Thusby aggregating the transmission of delay tolerant and non-delay tolerantdata packets an improvement is achieved with respect to an efficiencywith which the data packets are compared to the amount of signallingdata required to communicate the data packets.

S14. If however the communications conditions are below a predeterminedthreshold then the delay tolerant and non-delay tolerant data packetsare maintained in the input buffer until the predetermined conditionsare satisfied. As such the processing proceeds back to step S4 but couldproceed to step S1 to receive new data packets. In this example theradio communications conditions are not sufficient to transmit the delaytolerant or the non-delay tolerant data packets and in this example thenon-delay tolerant data packets may be discarded.

An example explanation of the respective predetermined conditions whichcan be applied in the example embodiment of the present technique isshown in FIG. 10. As can be seen from FIG. 10 there are three thresholdsA, B and C representing predetermined conditions for radiocommunications. As a first threshold A, if the radio conditions areabove a predetermined quality metric then there is no restriction on thetransmission of delay tolerant and non-delay tolerant data packets.However if the radio conditions are below the threshold A but are betterthan or equal to a threshold B which represents intermediate conditions,that is the channel quality metric is worse than threshold A but betterthan threshold B, then the communications terminal may buffer delaytolerant data packets until a predetermined amount of tolerant datapackets are present in the input buffer in which case the data packetsare transmitted. If however a non-delay tolerant data packet is receivedthen this data packet is transmitted immediately with any delay tolerantdata packets which are present in the input buffer.

If the radio conditions are worse than threshold B but better than athreshold C as determined by a channel quality metric of the radiocommunications channel then only the non-delay tolerant data packets aretransmitted. If however the quality metric of the radio communicationschannel is below threshold C then no data packets are transmitted andthese data packets are either buffered in the input buffer if they canbe delayed or if they cannot be delayed then for example the non-delaytolerant data packets.

Conditional Transmission Based on Available Power

As will be appreciated from the description above, in addition to thestate of radio communications for transmitting the data packets on theuplink, or as a separate condition, a decision as to whether to transmitdelay tolerant data packets or non-delay data packets may also beinfluenced by a current level of power which is available to thecommunications terminal. For example, depending on the amount of poweravailable, for example if this is below a predetermined threshold, thenonly non-delay tolerant data may be transmitted. An illustrative exampleof the operation of a communications terminal to transmit data packetsdepending on an amount of power available to the communications terminalis shown in FIG. 11 which is summarised as follows:

S20. From a start position the communications terminal determines anamount of delay tolerant and non-delay tolerant data packets in theinput buffer in step S22.

S24. The controller determines if there is one or more non-delaytolerant data packet received in the input buffer. If yes thenprocessing proceeds to step S26 and the current coverage in terms of theradio communications conditions are determined and the relativethresholds applied to determine whether or not the non-delay tolerantdata should be transmitted as explained above with reference to FIG. 10.

S28. If there is no non-delay tolerant data packet being received thenthe current size of the input buffer is determined.

S30. If the number delay tolerant data packets in the input buffer islarger than a predetermined threshold then processing proceeds to S26 todetermine whether or not the data packets should be transmitted inaccordance with the current state of radio communication conditions asrepresented by FIG. 10.

S32. If the number of data packets of delay tolerant data has notreached a predetermined number then the controller determines thecurrent amount of power available for transmitting data packets.

S34. If the determined power is above a predetermined threshold thenprocessing proceeds to S26. Otherwise processing proceeds to step S36and the delay tolerant data packets are maintained in the input bufferand not transmitted and processing proceeds to step S22.

According to some examples, if the battery power level is below apredetermined level then the UE does not send the data. However, whenthe battery is being charged (i.e. main connected), UE may send the datapackets which are present in the input buffer. The transmission of thedelay and non-delay tolerant data packets can be therefore determined independence upon the remaining power in the battery (e.g. percentage) orif mains power is connected (Battery being charged) or not (batteryoperation).

Transmission on Handover

In one example embodiment the current state for radio communicationsincludes whether the communications terminal has detached or is about tohandover from a first infrastructure equipment of the mobilecommunications network and re-attached or is about to handover to asecond infrastructure equipment in accordance with a hand-overprocedure. If the communications terminal has performed or is about toperform a handover procedure, the controller is configured to transmitany delay tolerant and non-delay tolerant data packets from the inputbuffer to the mobile communications network. In one example, the delaytolerant and non-delay tolerant data packets are transmitted inaccordance with the abovementioned channel conditions and buffer statuseven if a handover occurs, but all non-delay tolerant and delay tolerantdata packets are transmitted if a tracking area update is performed.

According to another example embodiment, if there is a change in thestatus of the RRC connection of the UE then the UE transmits all of thedata packets from the input buffer.

For example, UE may keep the data in the buffer in idle mode. When UEneeds to change the RRC state e.g. Periodic Tracking Area Update (TAU)transmission, then the UE transmits all of the stored data packetsduring idle mode and TAU message.

Example Architecture

FIG. 12 provides a schematic diagram showing part of an adapted LTEmobile telecommunication system arranged in accordance with an exampleof the present disclosure. The system includes an adapted enhanced NodeB (eNB) 1001 connected to a core network 1008 which communicates data toa plurality of conventional LTE terminals 1003, 1007 and reducedcapability communications terminals 1002 within a coverage area (i.e.cell) 1004. Each of the reduced capability terminals 1002 has atransceiver unit 1005 which includes a receiver unit capable ofreceiving signals via a wireless access interface provided by the eNodeB1001 and a transmitter unit capable of transmitting signals via thewireless access interface.

In one example embodiment the example reduced capability terminals 1002include a processor 1708 and a controller 1704 which are adapted toperform the process steps referred to above with reference to FIGS. 7 to11. Thus, in this example configuration architecture the controller 1704forms the controller 704 shown in FIGS. 7 and 8 and includes an inputbuffer 720. Thus the controller 1704 includes the transmissioncontroller 732 which is shown in FIG. 8 and operates in combination withthe transceiver 1006 which is shown in FIG. 8 as receiver 702 andtransmitter 700.

In another example embodiment of the present technique which will beexplained below the eNodeB 1001 includes a scheduler 1009 which isadapted to perform the decision-making in order to perform thedetermination as to whether or not to grant uplink communicationsresources for the transmission of data packets from the input buffer 720to the eNodeB via the wireless access interface. This is explained inthe following section.

eNodeB Decision Making

As explained above the controller 1704 within the UE determines whetheror not to transmit the delay tolerant data packets or non-delay tolerantdata packets depending on a current state for radio communications andan amount of the data packets present in the input buffer 720. In oneembodiment, the eNodeB determines whether or not the data packets in theinput buffer 720 should be transmitted or not depending on thepredetermined conditions as set out above. Such an example embodimentwould utilise the message exchange as shown in FIG. 13. As shown in FIG.13, the UE 104 transmits to the eNodeB 101 a current state of the inputbuffer in respect of the number of each of the different types of datapackets in the input buffer as indicated by a message 800 as shown inFIG. 13. Thus in FIG. 13 the message 800 may be transmitted on a regularbasis using MAC layer signalling indicating a status of the input bufferto the eNodeB. Accordingly, when the UE 104 makes a request to transmitthe data packets using an PRACH or PUCCH message the eNodeB candetermine whether or not to grant the uplink resources depending on thecurrent status of the input buffer and/or the current state of the radiocommunications channel.

FIG. 14 provides a more detailed example of the scheduling of delaytolerant data packets or non-delay tolerant data packets as determinedby the mobile communications network. As shown in FIG. 14, in step S40the UE determines whether it has delay tolerant data to transmit. If theUE does have delay tolerant data transmit then the UE transmits an RRCconnection set up message including the delay tolerant input bufferstatus and power supply status information in a message M1. Thus themessage M1 which is an RRC connection set up request is adapted toinclude an indication of the amount of delay tolerant data packets inthe input buffer and a status of a power supply of the UE.

There then follows a sequence of message exchanges and processesreferred to generally as a bearer setup S42 in which the UE 104 and thenetwork 102 establish a bearer including a quality of service and apriority configuration for transmitting the data packets.

The UE then determines a current coverage or channel quality state whichis available for transmitting the data packets on the uplink sharedchannel S44. The UE then communicates a measurement report of thecurrent state for radio communications using a message M2 and transmitsa scheduling request to access the shared uplink resources fortransmitting the data packets using a message M4 and transmits a statusof its input buffer in a message M6. The eNodeB then schedules anallocation of the uplink resources in a step S46 and then transmits thescheduling of the uplink resources in a grant message M8 which istransmitted to the UE on the downlink PDCCH. Thus, is accordance withthe operation represented in FIG. 14, a decision as to whether to grantthe uplink resources is performed by an adapted scheduler in step S46based on the report of the current channel state and the buffer statusof the input buffer of the UE and/or a current state of the power supplyof the UE. Based on this information the scheduler and the eNodeBapplies the predetermined conditions for determining whether to grantuplink resources to transmit the data packets which may also depend onthe number of delay tolerant and non-delay tolerant data packets presentin the input buffer.

Application to MTC-Type Devices

The abovementioned embodiments can be used by MTC terminals. To supportMTC terminals, it has been proposed to introduce a “virtual carrier”operating within a bandwidth of one or more “host carriers”: theproposed virtual carrier concept preferably integrates within thecommunications resources of conventional OFDM based radio accesstechnologies and subdivides frequency spectrum in a similar manner toOFDM. Unlike data transmitted on a conventional OFDM type downlinkcarrier, data transmitted on the virtual carrier can be received anddecoded without needing to process the full bandwidth of the downlinkOFDM host carrier. Accordingly, data transmitted on the virtual carriercan be received and decoded using a reduced complexity receiver unit:with concomitant benefits such as increased simplicity, increasedreliability, reduced form-factor and lower manufacturing cost. Thevirtual carrier concept is described in a number of co-pending patentapplications (including GB 1101970.0 [2], GB 1101981.7 [3], GB 1101966.8[4], GB 1101983.3 [5], GB 1101853.8 [6], GB 1101982.5 [7], GB 1101980.9[8] and GB 1101972.6 [9]), the contents of which are incorporated hereinby reference.

Accordingly it will be appreciated that the techniques described abovein which data packets are transmitted as a function of their toleranceto delay and a state for radio communications can be used with MTCdevices transmitting or receiving data on a virtual carrier. As has beenexplained above, because the reduced complexity terminals 1002 receiveand transmit data across a reduced bandwidth on the uplink and downlinkvirtual carriers, the complexity, power consumption and cost of thetransceiver unit 1006 needed to receive and decode downlink data and toencode and transmit uplink data is reduced compared to the transceiverunit 1005 provided in the conventional LTE terminals 1003.

In some examples, the virtual carrier inserted within the host carriercan be used to provide a logically distinct “network within a network”.In other words data being transmitted via the virtual carrier can betreated as logically and physically distinct from the data transmittedby the host carrier network. The virtual carrier can therefore be usedto implement a so-called dedicated messaging network (DMN) which is“laid over” a conventional network and used to communicate messagingdata to DMN terminals (i.e. virtual carrier terminals).

Various modifications can be made to examples of the present disclosure.Furthermore, it will be understood that the general principle ofinserting a virtual carrier on a subset of uplink or downlink resourcescan be applied to any suitable mobile telecommunication technology andneed not be restricted to systems employing an LTE based radiointerface.

According to another example aspect there is provide a communicationsterminal comprising a transmitter configured to transmit signals to awireless communications network via a wireless access interface providedby the wireless communications network. The communications terminal alsocomprises a receiver configured to receive signals from the wirelesscommunications network, and a controller configured to control thetransmitter and the receiver to transmit and receive the signals,wherein the controller includes an input buffer for receiving datapackets for transmission as the signals via the wireless accessinterface. The controller is configured to identify whether the receiveddata packets are delay tolerant or non-delay tolerant, to determine incombination with signals received from the receiver an indication of acurrent state for radio communications formed by the wireless accessinterface for transmitting the data packets via the wireless accessinterface, and in accordance with the predetermined conditions whichinclude a current state for radio communications and an amount of thedelay tolerant data packets in the input buffer and an amount of thenon-delay tolerant packets in the input buffer either to transmit thenon-delay tolerant data packets or to transmit the non-delay tolerantdata packets and the delay tolerant data packets from the input bufferto the mobile communications network using the transmitter, ormaintaining the delay tolerant or non-delay tolerant data packets in theinput buffer until the predetermined conditions are satisfied.

The following numbered clauses provide further example aspects andfeatures of the present technique:

1. A communications terminal comprising

a transmitter configured to transmit signals to a wirelesscommunications network via a wireless access interface provided by thewireless communications network, and

a receiver configured to receive signals from the wirelesscommunications network, and

a controller configured to control the transmitter and the receiver totransmit and receive the signals, wherein the controller includes aninput buffer for receiving data packets for transmission as the signalsby the communications terminal via the wireless access interface, andthe controller is configured

to identify whether the received data packets are delay tolerant ornon-delay tolerant,

to determine in combination with signals received from the receiver anindication of a current state for radio communications formed by thewireless access interface for transmitting the data packets via thewireless access interface, and

in accordance with predetermined conditions which include a currentstate for radio communications and an amount of the delay tolerant datapackets in the input buffer and an amount of the non-delay tolerantpackets in the input buffer either to transmit the non-delay tolerantdata packets or to transmit the non-delay tolerant data packets and thedelay tolerant data packets from the input buffer to the mobilecommunications network using the transmitter, or maintaining the delaytolerant or non-delay tolerant data packets in the input buffer untilthe predetermined conditions are satisfied.

2. A communications terminal according to clause 1, comprising

a power monitoring circuit for monitoring an amount of power which isavailable to the transmitter and the receiver to transmit or to receivethe data via the wireless access interface, wherein the predeterminedconditions used by the controller to determine whether to transmit thenon-delay tolerant data packets or to transmit the non-delay tolerantdata packets and the delay tolerant data packets from the input bufferto the mobile communications network using the transmitter includes theamount of power available to the transmitter to transmit the datapackets in combination with the current state for radio communications.

3. A communications terminals according to clause 2, wherein thecontroller is configured to determine whether the amount of poweravailable is above or below a power threshold and if the amount of poweravailable is below the power threshold only transmitting the non-delaytolerant data packets, and if the amount of power available is above thepower threshold transmitting the non-delay tolerant data packets and thedelay tolerant data packets.

4. A communications terminal according to clause 1, 2 or 3, wherein thecurrent state of radio communications is determined by the controllerfrom signals received by the receiver from data transmitted by themobile communications network, the receiver providing to the controllera channel quality measurement indicator, and the predeterminedconditions include whether the channel quality measurement indicatorindicates a quality for radio communications above a first predeterminedlevel, and if the channel quality measurement for radio communicationsis above the first predetermined threshold the controller is configuredto transmit the delay tolerant data packets or non-delay tolerant datapackets when present in the input buffer.

5. A communications terminal according to clause 4, wherein thepredetermined conditions include whether the channel quality measurementindicator indicates a quality for radio communications below the firstpredetermined threshold and above a second predetermined level, and ifthe channel quality measurement for radio communications is above thesecond predetermined threshold and below the first predeterminedthreshold the controller is configured to transmit the delay tolerantdata packets if the number of delay tolerant data packets in the inputbuffer has reached a predetermined amount, and to transmit the delaytolerant data packets from the input buffer with non-delay tolerant datapackets, when there is at least one non-delay tolerant data packetpresent in the input buffer.

6. A communications terminal according to clause 4 or 5, wherein thepredetermined conditions include whether the channel quality measurementindicator indicates a quality for radio communications below the firstpredetermined threshold, below the second predetermined threshold andabove a third predetermined level, and if the channel qualitymeasurement for radio communications is above the third predeterminedthreshold and below the first and second predetermined thresholds thecontroller is configured to transmit the non-delay tolerant data packetsand to maintain the non-delay tolerant data packets in the input bufferuntil the channel quality measurement indicator indicates a qualityabove the first or second predetermined threshold.

7. A communications terminal according to any of clauses 1 to 6, whereinthe current state for radio communications includes whether thecommunications terminal has detached from a first infrastructureequipment of the mobile communications network and re-attached to asecond infrastructure equipment in accordance with a hand-overprocedure, and if the communications terminal has performed a handoverprocedure, the controller is configured to transmit any delay tolerantand non-delay tolerant data packets from the input buffer to the mobilecommunications network.

8. A method of communicating data from a communications terminal to awireless communications network, the method comprising

transmitting signals to the wireless communications network via awireless access interface provided by the wireless communicationsnetwork,

receiving signals from the wireless communications network, and

controlling the transmitting and the receiving of the signals, whereinthe controlling includes

receiving data packets for transmission by the communications terminalvia the wireless access interface,

storing the data packets in an input buffer,

identifying whether the received data packets are delay tolerant ornon-delay tolerant,

determining in combination with the received signals an indication of acurrent state for radio communications formed by the wireless accessinterface for transmitting the data packets via the wireless accessinterface, and

in accordance with predetermined conditions which include a currentstate for radio communications and an amount of the delay tolerant datapackets in an input buffer and an amount of the non-delay tolerantpackets in the input buffer determining whether

to transmit the non-delay tolerant data packets, or

to transmit the non-delay tolerant data packets and the delay tolerantdata packets from the input buffer to the mobile communications networkusing the transmitter, or

to maintain the delay tolerant or delay tolerant data packets in theinput buffer until the predetermined conditions are satisfied.

9. A method of communicating according to clause 8, comprising

monitoring an amount of power which is available to transmit or toreceive the data via the wireless access interface, wherein thepredetermined conditions for determining whether to transmit thenon-delay tolerant data packets or to transmit the non-delay tolerantdata packets and the delay tolerant data packets from the input bufferto the mobile communications network includes the amount of poweravailable to the transmitter to transmit the data packets in combinationwith the current state for radio communications.

10. A method of communicating according to clause 9, wherein thepredetermined conditions for determining whether to transmit thenon-delay tolerant data packets or to transmit the non-delay tolerantdata packets and the delay tolerant data packets from the input bufferto the mobile communications network includes

determining whether the amount of power available is above or below apower threshold and if the amount of power available is below the powerthreshold only transmitting the non-delay tolerant data packets, and ifthe amount of power available is above the power threshold transmittingthe non-delay tolerant data packets and the delay tolerant data packets.

11. A method of communicating according to clause 8, 9 or 10, comprising

determining the current state of radio communications from the signalsreceived from the mobile communications network,

providing to the controller a channel quality measurement indicator, andthe predetermined conditions for determining whether to transmit thenon-delay tolerant data packets or to transmit the non-delay tolerantdata packets and the delay tolerant data packets from the input bufferto the mobile communications network include whether the channel qualitymeasurement indicator indicates a quality for radio communications abovea first predetermined level, and if the channel quality measurement forradio communications is above the first predetermined threshold

transmitting the delay tolerant data packets or non-delay tolerant datapackets when present in the input buffer.

12. A method of communicating according to clause 11, wherein thepredetermined conditions include whether the channel quality measurementindicator indicates a quality for radio communications below the firstpredetermined threshold and above a second predetermined level, and ifthe channel quality measurement for radio communications is above thesecond predetermined threshold and below the first predeterminedthreshold

transmitting the delay tolerant data packets if the number of delaytolerant data packets in the input buffer has reached a predeterminedamount, and to transmit the delay tolerant data packets from the inputbuffer with and non-delay tolerant data packets, when there is at leastone non-delay tolerant data packet present in the input buffer.

13. A method of communicating according to clause 11 or 12, wherein thepredetermined conditions include whether the channel quality measurementindicator indicates a quality for radio communications below the firstpredetermined threshold, below the second predetermined threshold andabove a third predetermined level, and if the channel qualitymeasurement for radio communications is above the third predeterminedthreshold and below the first and second predetermined thresholdstransmitting the non-delay tolerant data packets and to maintain thedelay tolerant data packets in the input buffer until the channelquality measurement indicator indicates a quality above the first orsecond predetermined threshold.

14. A method of communicating according to any of clauses 8 to 13,wherein the current state for radio communications includes whether thecommunications terminal has detached from a first infrastructureequipment of the mobile communications network and re-attached to asecond infrastructure equipment in accordance with a hand-overprocedure, and if the communications terminal has performed a handoverprocedure, transmitting any delay tolerant and non-delay tolerant datapackets from the input buffer to the mobile communications network.

15. A computer program providing computer executable software, whichwhen loaded onto a computer and executed performs the method accordingto any of clauses 8 to 13.

The invention claimed is:
 1. A communications terminal comprising: atransmitter configured to transmit signals to a wireless communicationsnetwork via a wireless access interface provided by the wirelesscommunications network, and a receiver configured to receive signalsfrom the wireless communications network, and a controller configured tocontrol the transmitter and the receiver to transmit and receive thesignals, wherein the controller includes an input buffer for receivingdata packets for transmission as the signals by the communicationsterminal via the wireless access interface, and the controller isconfigured: to identify whether the received data packets are delaytolerant or non-delay tolerant, to determine in combination with signalsreceived by the receiver an indication of a current state for radiocommunications formed by the wireless access interface for transmittingthe data packets via the wireless access interface, and in accordancewith predetermined conditions, which include the current state for radiocommunications, an amount of the delay tolerant data packets in theinput buffer, and an amount of the non-delay tolerant packets in theinput buffer to one of: transmit the non-delay tolerant data packets tothe mobile communications network using the transmitter, aggregate thenon-delay tolerant data packets and the delay tolerant data packetstogether, and transmit the aggregated non-delay tolerant data packetsand delay tolerant data packets to the mobile communications networkusing the transmitter, and maintain both the delay tolerant data packetsand the non-delay tolerant data packets in the input buffer until thepredetermined conditions are satisfied.
 2. The communications terminalas claimed in claim 1, comprising: a power monitoring circuit configuredto monitor an amount of power which is available to the transmitter andthe receiver to transmit or to receive the data via the wireless accessinterface, wherein the predetermined conditions used by the controllerto determine whether to transmit the non-delay tolerant data packets orto transmit the non-delay tolerant data packets and the delay tolerantdata packets from the input buffer to the mobile communications networkusing the transmitter includes the amount of power available to thetransmitter to transmit the data packets in combination with the currentstate for radio communications.
 3. The communications terminals asclaimed in claim 2, wherein the controller is configured to determinewhether the amount of power available is above or below a powerthreshold and if the amount of power available is below the powerthreshold to only transmit the non-delay tolerant data packets, and ifthe amount of power available is above the power threshold to transmitthe non-delay tolerant data packets and the delay tolerant data packets.4. The communications terminal as claimed in claim 1, wherein thecurrent state of radio communications is determined by the controllerfrom signals received by the receiver from data transmitted by themobile communications network, the receiver providing to the controllera channel quality measurement indicator, and the predeterminedconditions include whether the channel quality measurement indicatorindicates a quality for radio communications above a first predeterminedlevel, and if the channel quality measurement for radio communicationsis above the first predetermined threshold the controller is configuredto transmit the delay tolerant data packets and non-delay tolerant datapackets when present in the input buffer.
 5. The communications terminalas claimed in claim 4, wherein the predetermined conditions includewhether the channel quality measurement indicator indicates a qualityfor radio communications below the first predetermined threshold andabove a second predetermined level, and if the channel qualitymeasurement for radio communications is above the second predeterminedthreshold and below the first predetermined threshold the controller isconfigured to transmit the delay tolerant data packets if the number ofdelay tolerant data packets in the input buffer has reached apredetermined amount, and to transmit the delay tolerant data packetsfrom the input buffer with non-delay tolerant data packets, when thereis at least one non-delay tolerant data packet present in the inputbuffer.
 6. The communications terminal as claimed in claim 4, whereinthe predetermined conditions include whether the channel qualitymeasurement indicator indicates a quality for radio communications belowthe first predetermined threshold, below the second predeterminedthreshold and above a third predetermined level, and if the channelquality measurement for radio communications is above the thirdpredetermined threshold and below the first and second predeterminedthresholds the controller is configured to transmit the non-delaytolerant data packets and to maintain the non-delay tolerant datapackets in the input buffer until the channel quality measurementindicator indicates a quality above the first or second predeterminedthreshold.
 7. The communications terminal as claimed in claim 1, whereinthe current state for radio communications includes whether thecommunications terminal has detached from a first infrastructureequipment of the mobile communications network and re-attached to asecond infrastructure equipment in accordance with a hand-overprocedure, and if the communications terminal has performed a handoverprocedure, the controller is configured to transmit any delay tolerantand non-delay tolerant data packets from the input buffer to the mobilecommunications network.
 8. A method of communicating data from acommunications terminal to a wireless communications network, the methodcomprising: transmitting, with a transmitter, signals to the wirelesscommunications network via a wireless access interface provided by thewireless communications network, receiving, with a receiver, signalsfrom the wireless communications network, and controlling, with acontroller, the transmitting and the receiving of the signals, whereinthe controlling includes receiving data packets for transmission by thecommunications terminal via the wireless access interface, storing thedata packets in an input buffer, identifying whether the received datapackets are delay tolerant or non-delay tolerant, determining incombination with the received signals an indication of a current statefor radio communications formed by the wireless access interface fortransmitting the data packets via the wireless access interface, and inaccordance with predetermined conditions which include a current statefor radio communications and an amount of the delay tolerant datapackets in an input buffer and an amount of the non-delay tolerantpackets in the input buffer determining whether to one of: transmit thenon-delay tolerant data packets to the wireless communications networkusing the transmitter, aggregate the non-delay tolerant data packets andthe delay tolerant data packets together and transmit the aggregatedon-delay tolerant data packets and the delay tolerant data packets tothe wireless communications network using the transmitter, and maintainboth the delay tolerant data packets and the non-delay tolerant datapackets in the input buffer until the predetermined conditions aresatisfied.
 9. The method of communicating as claimed in claim 8,comprising: monitoring an amount of power which is available to transmitor to receive the data via the wireless access interface, wherein thepredetermined conditions for determining whether to transmit thenon-delay tolerant data packets or to transmit the non-delay tolerantdata packets and the delay tolerant data packets from the input bufferto the mobile communications network includes the amount of poweravailable to the transmitter to transmit the data packets in combinationwith the current state for radio communications.
 10. The method ofcommunicating as claimed in claim 9, wherein the predeterminedconditions for determining whether to transmit the non-delay tolerantdata packets or to transmit the non-delay tolerant data packets and thedelay tolerant data packets from the input buffer to the mobilecommunications network includes whether the amount of power available isabove or below a power threshold and if the amount of power available isbelow the power threshold only transmitting the non-delay tolerant datapackets, and if the amount of power available is above the powerthreshold transmitting the non-delay tolerant data packets and the delaytolerant data packets.
 11. The method of communicating as claimed inclaim 8, comprising: determining the current state of radiocommunications from the signals received from the mobile communicationsnetwork, providing to the controller a channel quality measurementindicator, and the predetermined conditions for determining whether totransmit the non-delay tolerant data packets or to transmit thenon-delay tolerant data packets and the delay tolerant data packets fromthe input buffer to the mobile communications network include whetherthe channel quality measurement indicator indicates a quality for radiocommunications above a first predetermined level, and if the channelquality measurement for radio communications is above the firstpredetermined threshold, transmitting the delay tolerant data packets ornon-delay tolerant data packets when present in the input buffer. 12.The method of communicating as claimed in claim 11, wherein thepredetermined conditions include whether the channel quality measurementindicator indicates a quality for radio communications below the firstpredetermined threshold and above a second predetermined level, and ifthe channel quality measurement for radio communications is above thesecond predetermined threshold and below the first predeterminedthreshold the method further comprises: transmitting the delay tolerantdata packets if the number of delay tolerant data packets in the inputbuffer has reached a predetermined amount, and to transmit the delaytolerant data packets from the input buffer with and non-delay tolerantdata packets, when there is at least one non-delay tolerant data packetpresent in the input buffer.
 13. The method of communicating as claimedin claim 11, wherein the predetermined conditions include whether thechannel quality measurement indicator indicates a quality for radiocommunications below the first predetermined threshold, below the secondpredetermined threshold and above a third predetermined level, and ifthe channel quality measurement for radio communications is above thethird predetermined threshold and below the first and secondpredetermined thresholds, the method further comprises transmitting thenon-delay tolerant data packets and to maintain the delay tolerant datapackets in the input buffer until the channel quality measurementindicator indicates a quality above the first or second predeterminedthreshold.
 14. The method of communicating as claimed in claim 8,wherein the current state for radio communications includes whether thecommunications terminal has detached from a first infrastructureequipment of the mobile communications network and re-attached to asecond infrastructure equipment in accordance with a hand-overprocedure, and if the communications terminal has performed a handoverprocedure, the method further comprises transmitting any delay tolerantand non-delay tolerant data packets from the input buffer to the mobilecommunications network.
 15. A non-transitory computer-readable mediumencoded with computer-readable instructions that, when executed by aprocessor, cause the processor to perform the method according to claim8.